66RFE Valve Body Questions

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PARAMGUY

Junior Member
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Jul 5, 2025
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Location
Pittsburgh, PA
Ram Year
2013
Engine
5.7L V8
I did some searching but have some specific quesitons...

I have a 2013 Ram 2500 Crew cab 4x4 with the 5.7L gas and the 66RFE transmission. Truck is in Western Pennsylvania.
This started about a year ago but I drive a company truck a lot so this has been a back burnered project that I need to resolve. Issue is with shifting but I need some guidance on narrowing down the problem and thoughts on next steps. Truck started shifting hard a litle here and there and progressively got worse. My father borrowed it to tow camper and he was flooring it uphill which popped it into service mode and pushed trans temp up to 200 ish and triggered check engine light. Since then it's been a rabbit hole trying to rectify.

Symptoms:
- Truck will drive around town ok, If it needs to go into 5th/6th gears it starts to have issues, especially when trans temp is above 140
- If on highway I notice the issue is with downshifting primarily for hill climbs. It tends to jump a bit and then goes into limp mode. Usually happens 60-65 mph @ 2000-2200 rpm. If I turn truck off and back on, it will reset and be fine again.

Codes:
- Typically tied to 4/5/6 incorrect gear ratio.

Troubleshoot thus far:
- Trans has been drained and refilled and when this was done I swapped the screw on and the flat filters.
- I thought it was a temp issue so I bypassed the thermal block thing up by radiator
- Moved to an aftermarket trans cooler that is bigger than the original one - temps no run mid 150's - mid 160's while driving in summer 85-90 degree days
- Replaced input and output shaft speed sensors

Same issue still exists

Thoughts on Next Steps:
- I am thinking the issue is with the valve body or the solenoid, or both. I am noticing a minor squeal noise when it shifts if I am babying the throttle around 35-45 mph - I think this is the 4/5 shift but not entirely sure.
- SIDE NOTE - Truck sat for several months this winter and battery died. I did get on P2610 code but this cleared and has not returned, and has not been present during any of the other times when driving with hard shifts and such, so it makes me think more towards
Valve body and solenoid vs ECM/TCM

I am considering swapping both the Valve Body and the Solenoid but wanted your opinion on that idea, and also input on determining type.

I was under the truck today and I see the black harness plug on the drivers side of trans by shift linkage. The color of the solenoid side of the plug is gray, does that matter? most of what I am finding online is a white one.

Also, I am having a difficult time finding 66RFE parts, will the 68RFE vale bodies work?

I saw in another thread where it was kind of mentioned that I'd need to do a relearn/flash on the computer? Can someone ellaborate on this

Thank you in advance
 

Megas_XLT

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Memphis
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Hey let me explain to you from my experience on my truck I have the same issue but the code was related to the 5th gear and the 6th gear But the 4th gear did show up later after I rebuilt it Now I could probably have avoided if I did went and bought the valve body but I decided to find and buy whole new transmission and I haven't had any issue ever since

Also, I am having a difficult time finding 66RFE parts, will the 68RFE vale bodies work? < No to my understanding they use more pressure but I could be wrong I just know that they use different software and pressure

I saw in another thread where it was kind of mentioned that I'd need to do a relearn/flash on the computer? Can someone elaborate on this < Yes you're going to have to relearn the transmission let's say if you rebuilt it or swap a new transmission

I found a used transmission on eBay with 35,000 miles on it once I put the new transmission and recalibrate the transmission Because you I don't remember what code but it won't shift gear properly
 
Last edited:

NewBlackDak

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6.7L Cummins
I bought a RevMax 68RFE valve body and solenoid pack and installed it in my 66RFE last year. It has been working great. They now have dedicated 66RFE part on their website. I took a chance, because the part numbers for the VB and solenoid pack were the same and they looked identical. No idea why they're charging so much more for the 66 version since it's the same dang part. Any new VB requires a transmission re-learn. I was having the gear ratio codes too.
 

DripJust

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Location
Canada Ontario
Ram Year
2009
Engine
5.7 Hemi
Anyone know if it's possible to swap a 545 with either a 65 or 66 i to a 2009 1500 ?
 

JesseG0720

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Joined
Jun 8, 2026
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Location
Anaheim, CA
Ram Year
2015
Engine
5.7
I did some searching but have some specific quesitons...

I have a 2013 Ram 2500 Crew cab 4x4 with the 5.7L gas and the 66RFE transmission. Truck is in Western Pennsylvania.
This started about a year ago but I drive a company truck a lot so this has been a back burnered project that I need to resolve. Issue is with shifting but I need some guidance on narrowing down the problem and thoughts on next steps. Truck started shifting hard a litle here and there and progressively got worse. My father borrowed it to tow camper and he was flooring it uphill which popped it into service mode and pushed trans temp up to 200 ish and triggered check engine light. Since then it's been a rabbit hole trying to rectify.

Symptoms:
- Truck will drive around town ok, If it needs to go into 5th/6th gears it starts to have issues, especially when trans temp is above 140
- If on highway I notice the issue is with downshifting primarily for hill climbs. It tends to jump a bit and then goes into limp mode. Usually happens 60-65 mph @ 2000-2200 rpm. If I turn truck off and back on, it will reset and be fine again.

Codes:
- Typically tied to 4/5/6 incorrect gear ratio.

Troubleshoot thus far:
- Trans has been drained and refilled and when this was done I swapped the screw on and the flat filters.
- I thought it was a temp issue so I bypassed the thermal block thing up by radiator
- Moved to an aftermarket trans cooler that is bigger than the original one - temps no run mid 150's - mid 160's while driving in summer 85-90 degree days
- Replaced input and output shaft speed sensors

Same issue still exists

Thoughts on Next Steps:
- I am thinking the issue is with the valve body or the solenoid, or both. I am noticing a minor squeal noise when it shifts if I am babying the throttle around 35-45 mph - I think this is the 4/5 shift but not entirely sure.
- SIDE NOTE - Truck sat for several months this winter and battery died. I did get on P2610 code but this cleared and has not returned, and has not been present during any of the other times when driving with hard shifts and such, so it makes me think more towards
Valve body and solenoid vs ECM/TCM

I am considering swapping both the Valve Body and the Solenoid but wanted your opinion on that idea, and also input on determining type.

I was under the truck today and I see the black harness plug on the drivers side of trans by shift linkage. The color of the solenoid side of the plug is gray, does that matter? most of what I am finding online is a white one.

Also, I am having a difficult time finding 66RFE parts, will the 68RFE vale bodies work?

I saw in another thread where it was kind of mentioned that I'd need to do a relearn/flash on the computer? Can someone ellaborate on this

Thank you in advanc

Hey let me explain to you from my experience on my truck I have the same issue but the code was related to the 5th gear and the 6th gear But the 4th gear did show up later after I rebuilt it Now I could probably have avoided if I did went and bought the valve body but I decided to find and buy whole new transmission and I haven't had any issue ever since

Also, I am having a difficult time finding 66RFE parts, will the 68RFE vale bodies work? < No to my understanding they use more pressure but I could be wrong I just know that they use different software and pressure

I saw in another thread where it was kind of mentioned that I'd need to do a relearn/flash on the computer? Can someone elaborate on this < Yes you're going to have to relearn the transmission let's say if you rebuilt it or swap a new transmission

I found a used transmission on eBay with 35,000 miles on it once I put the new transmission and recalibrate the transmission Because you I don't remember what code but it won't shift gear properly
Megas_XLT: Your 4th gear code showed up after you rebuilt the transmission? So did you end up replacing the valve body as well? Or just changed the entire transmission?
 

Burla

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2010 Hemi Reg Cab 4x4
Engine
Hemi
Take your dad behind the woodshed like he did to you when you was young. RFE will service you, but it is one transmission you cannot abuse.

rfe's tend to lose od first, most of the time it is the pistons in valve body.. Most of the rings at top of pistons combined with other cross leaks.

A good watch some member posted long ago, most likely you have these issues. You sound like a proper dude, you can easily rebuild this and avoid flashes and other stuff. maybe maybe not quick learn with new rebuild kit.

 

JesseG0720

Junior Member
Joined
Jun 8, 2026
Posts
2
Reaction score
0
Location
Anaheim, CA
Ram Year
2015
Engine
5.7
I did some searching but have some specific quesitons...

I have a 2013 Ram 2500 Crew cab 4x4 with the 5.7L gas and the 66RFE transmission. Truck is in Western Pennsylvania.
This started about a year ago but I drive a company truck a lot so this has been a back burnered project that I need to resolve. Issue is with shifting but I need some guidance on narrowing down the problem and thoughts on next steps. Truck started shifting hard a litle here and there and progressively got worse. My father borrowed it to tow camper and he was flooring it uphill which popped it into service mode and pushed trans temp up to 200 ish and triggered check engine light. Since then it's been a rabbit hole trying to rectify.

Symptoms:
- Truck will drive around town ok, If it needs to go into 5th/6th gears it starts to have issues, especially when trans temp is above 140
- If on highway I notice the issue is with downshifting primarily for hill climbs. It tends to jump a bit and then goes into limp mode. Usually happens 60-65 mph @ 2000-2200 rpm. If I turn truck off and back on, it will reset and be fine again.

Codes:
- Typically tied to 4/5/6 incorrect gear ratio.

Troubleshoot thus far:
- Trans has been drained and refilled and when this was done I swapped the screw on and the flat filters.
- I thought it was a temp issue so I bypassed the thermal block thing up by radiator
- Moved to an aftermarket trans cooler that is bigger than the original one - temps no run mid 150's - mid 160's while driving in summer 85-90 degree days
- Replaced input and output shaft speed sensors

Same issue still exists

Thoughts on Next Steps:
- I am thinking the issue is with the valve body or the solenoid, or both. I am noticing a minor squeal noise when it shifts if I am babying the throttle around 35-45 mph - I think this is the 4/5 shift but not entirely sure.
- SIDE NOTE - Truck sat for several months this winter and battery died. I did get on P2610 code but this cleared and has not returned, and has not been present during any of the other times when driving with hard shifts and such, so it makes me think more towards
Valve body and solenoid vs ECM/TCM

I am considering swapping both the Valve Body and the Solenoid but wanted your opinion on that idea, and also input on determining type.

I was under the truck today and I see the black harness plug on the drivers side of trans by shift linkage. The color of the solenoid side of the plug is gray, does that matter? most of what I am finding online is a white one.

Also, I am having a difficult time finding 66RFE parts, will the 68RFE vale bodies work?

I saw in another thread where it was kind of mentioned that I'd need to do a relearn/flash on the computer? Can someone ellaborate on this

Thank you in advance
Hello, I am having the same issues as you described. Did you end up changing your valve body and did that fix your problems?
 
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